This invention relates to a refrigeration oil composition and more specifically, to a refrigeration oil composition which is effective for the prevention of seizure, for example, of sliding parts or portions and also for the inhibition of valve coking phenomenon in a refrigerator operating in the atmosphere of a refrigerant (Freon) and is free from corroding such portions.
A refrigeration oil is a lubrication oil which is employed to maintain the lubricity of sliding portions of a refrigerator and hence to avoid wearing and/or seizure of the sliding portions. Such a refrigeration oil is obviously required to have a high degree of lubrication characteristic. Besides, it is also required to remain stable both thermally and chemically even in a refrigerant (Freon) and thus not to give any corrosive action to sliding portions (metals), and further not to produce any sludge on valve portions.
As a refrigeration oil capable of satisfying such requirements, Japanese Patent Provisional Publication No. 8294/1982 discloses a refrigeration oil composition formulated with mineral oil by adding thereto a variety of sulfur compounds to an overall sulfur content of 0.14 wt.%. The above-proposed refrigeration oil composition has improved lubricating capacity and lower viscosity, but it is still unknown as to its stability in a refrigerant such as Freon.